"While our research reaffirmed the risk of stroke among patients with heart disease, the surprise was that the risk was so high in the month after a heart attack," says Veronique Roger, M.D., M.P.H., the Mayo Clinic cardiologist who led the study.

"A lot of patients survive heart attacks today, which is why this study is so relevant," she says. "It emphasizes the importance of worrying about other things that can happen beyond heart attacks, stroke being one of them."

Researchers reviewed the medical records of 2,160 patients who received care for a heart attack at Mayo Clinic in Rochester, Minn., between 1979 and 1998 to see whether the patients had a stroke and/or died after the heart attack. Patients were followed for about six years.

In addition to the high risk in the first 30 days, the stroke risk remained two to three times higher than expected during the first three years following the heart attack. Older age, previous stroke and diabetes increased the risk for stroke, Dr. Roger says. Strokes were associated with a large increase in the risk for death after a heart attack, she says.

Researchers also discovered that the risk of stroke did not change over time. In the 20 years studied, the risk of stroke did not decrease over that period, Dr. Roger says.

The results can serve as a wake-up call to health care providers to know about this increased risk of stroke. Heart attack patients take certain medications, such as beta blockers, aspirin and those aimed at reducing cholesterol levels, which help with improving their long-term health, she says.